Issue #2130811 by alexpott, Gábor Hojtsy, vijaycs85, sun, Wim Leers: Use config schema in saving and validating configuration form to ensure data is consistent and correct.

Issue #1973498 by vijaycs85, yched, saki007ster: Provide config schema to field types and storage in taxonomy module.

Issue #1919208 by vijaycs85, rahuldolas123, Gábor Hojtsy: Create configuration schemas for taxonomy module.